Extrusion of polyurethane composite materials

ABSTRACT

Methods of extruding polyurethane composite materials are described. One method includes introducing at least one polyol and inorganic filler to a first conveying section of the extruder, transferring the at least one polyol and inorganic filler to a first mixing section of an extruder, mixing the at least one polyol and the inorganic filler in the first mixing section, transferring the mixed at least one polyol and inorganic filler to a second conveying section of the extruder, introducing a di- or poly-isocyanate to the second conveying section, transferring the mixed at least one polyol and inorganic filler and the di- or poly-isocyanate to a second mixing section, mixing the mixed at least one polyol and inorganic filler with the di- or poly-isocyanate in the second mixing section of the extruder to provide a composite mixture, and transferring the composite mixture to an output end of the extruder. Other related methods are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 11/691,456, filed on Mar.26, 2007, which claims the priority benefit of provisional applications60/785,726, filed Mar. 24, 2006 and 60/785,749, filed Mar. 24, 2006. Allof these documents are hereby incorporated by reference in theirentireties.

BACKGROUND OF THE INVENTION

1. Field

The invention relates to foamed and nonfoamed polymeric material, andmore particularly polyurethane composite materials, and methods forextruding the same.

2. Description of the Related Technology

Polymeric composite materials that contain organic or inorganic fillermaterials have become desirable for a variety of uses because of theirexcellent mechanical properties, weathering stability, and environmentalfriendliness.

These materials can be are relatively low density, due to their foaming,or high density when unfoamed, but are extremely strong, due to thereinforcing particles or fibers used throughout. Their polymer contentalso gives them good toughness (i.e., resistance to brittle fracture),and good resistance to degradation from weathering when they are exposedto the environment. This combination of properties renders somepolymeric composite materials very desirable for use in buildingmaterials, such as roofing materials, decorative or architecturalproducts, outdoor products, insulation panels, and the like.

SUMMARY OF THE INVENTION

Described herein are extrusion processes as related to polymericcomposite materials. More particularly, the extrusion processes relatedto polyurethane composite materials. In some embodiments, highly filledpolyurethane composite materials are extruded. Such materials may thenbe shaped and formed into solid surface articles. Articles comprisingthe polyurethane composite material as described herein are suitable forstructure, building, and outdoor applications.

In one embodiment, a method of forming a polymeric composite materialincludes introducing at least one polyol and inorganic filler to a firstconveying section of the extruder, transferring the at least one polyoland inorganic filler to a first mixing section of an extruder, mixingthe at least one polyol and the inorganic filler in the first mixingsection, transferring the mixed at least one polyol and inorganic fillerto a second conveying section of the extruder, introducing a di- orpoly-isocyanate to the second conveying section, transferring the mixedat least one polyol and inorganic filler and the di- or poly-isocyanateto a second mixing section, mixing the mixed at least one polyol andinorganic filler with the di- or poly-isocyanate in the second mixingsection of the extruder to provide a composite mixture, and transferringthe composite mixture to an output end of the extruder.

In some embodiments, the composite mixture includes about 40 to about 85weight percent of the inorganic filler. In some embodiments, thecomposite mixture includes about 60 to about 85 weight percent of theinorganic filler. In some embodiments, the composite mixture includesabout 65 to about 80 weight percent of the inorganic filler. Theinorganic filler may include many different types of filler. Onepreferred filler includes fly ash.

In certain embodiments, the conveying sections and mixing sections aredefined in terms of the screw segments and screw elements containedwithin the conveying or mixing section. In one embodiment, the firstconveying section includes one or more transfer screws. In oneembodiment, the first mixing section includes a slotted screw. Inanother embodiment, the first mixing section includes a lobal screw. Inone embodiment, the first mixing section includes a lobal screw and aslotted screw.

In some embodiments, the second conveying section is located downstreamof a first conveying section. In some embodiments, the second conveyingsection is located downstream of a first mixing section. In someembodiments, the section conveying section includes one or more transferscrews.

In some embodiments, a second mixing section is located downstream of afirst mixing section. In some embodiments, a second mixing section islocated downstream of the second conveying section. In certainembodiments, the second mixing section is adjacent to the output end ofthe extruder. In certain embodiments, the second mixing station includesa reverse screw. In certain embodiments, the reverse screw includes areverse slotted screw.

In some embodiments, the method may further include adding one or morecomponents of the composite mixture in the first conveying section ofthe extruder. Such additional components are further described herein.In one embodiment, the one or more components is selected from the groupconsisting of a catalyst, a surfactant, and a blowing agent. In otherembodiments, the one or more components may include one or more of across linker, a chain extender, and a coupling agent. In certain ofthese embodiments, the method further includes blending the one or morecomponents with the at least one polyol prior to introduction to thefirst conveying section.

In some embodiments, the method further includes mixing the mixed atleast one polyol and inorganic filler and the di- or poly-isocyanate ina third mixing section subsequent to the second conveying section andprior to the second mixing section. In some embodiments, the thirdmixing section includes a reverse screw. Certain embodiments, furtherinclude introducing fibrous material in the third conveying section. Incertain embodiments, the third conveying section is located between thesecond mixing section and the third mixing section.

As described herein, one or more fibrous materials may be extruded withthe polymeric composite material. In one embodiment, the method furtherincludes introducing fibrous material in the second conveying section.In certain embodiments, the method includes mixing the fibrous materialwith the mixed at least one polyol and inorganic filler and the di- orpoly-isocyanate in the second mixing section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an extruder including a screw shaft withvarious screw elements.

FIG. 2 is a drawing of a kneading block element.

FIG. 3 is an view of lobal screw elements in a twin screw extruder.

FIG. 4 is an illustration of one configuration of an extruder containingmultiple segments useful in the production of polyurethane compositematerials.

FIG. 5 is an illustration of one configuration of an extruder containingconveying and mixing section useful in the production of polyurethanecomposite materials.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Thermosetting polymeric composite materials may be made using anextruder. Such a process allows for thorough mixing of the variouscomponents of the polymeric composite material in the extruder. Thescrew and screw elements may be configured in various ways within anextruder to provide a substantially homogeneous mixture of the variouscomponents of the polymeric composite material. In addition, frictionand other forces may promote the reaction of various monomers and otheradditives that create a polymeric matrix in the polymeric compositematerial. Moreover, the various components of a polymeric compositematerial may be added in different orders and at different positions inan extruder. Thus, extrusion of polymeric composite material is adesirable method for providing a medium for reaction, controllingreaction ingredients and conditions, and mixing the various components.

An extruder having one or more material inputs may be used to form suchpolymeric composite materials. In accordance with certain embodiments, asingle screw extruder or a twin screw extruder may be used. Each screwof the extruder is mounted on a single shaft that transmits rotarymotion to the screw. In embodiments of a twin screw extruder, each screwmay be counter rotary to the other screw. The screw may comprise one ormore screw elements mounted on the rotating shaft. The screw mayalternatively be assembled from several separate screw elements, each ofwhich forms a portion of the screw operated within the extruder. Screwelements may be rotatably disposed in an appropriate sequence of theaxial shaft to form multiple segments of the screw. Various screwelements may include one or more of transport screw elements, lobalscrew elements, reverse screw elements, slotted screw elements, andkneading block elements. Various screw elements are described in U.S.Pat. Nos. 5,728,337, 6,136,246 and 6,908,573, which are herebyincorporated by reference.

Referring to FIG. 1, an extruder body 12 contains a screw body whichincludes a screw shaft 22 and a plurality of screw elements 23. Theextruder body 12 is outfitted with one or more vents 17 which allow airto escape from composite materials and the extruder body 12. The screwbody also includes one or more feed sections 19 where components of thepolymeric composite are fed into respective segments of the extruderbody 12. The extruder body also includes outlet 18. Outlet 18 may beequipped with a die. Screw elements 23 include a transport screwelements 15, a kneading blocks 16 and 40, a reverse transport screwelement 45, a lobal screw element 50, and a slotted screw element 55.While the various screw segments may be connected to or engaged with thescrew shaft 22 in any manner, spline fitting grooves may be mated to aspined screw shaft.

In some embodiments, transport screw elements have a flight that ishelically wound around the screw. The flight of the transport screw hasa positive pitch and therefore transfers materials in the extruderbarrel from the feed end to the output end. According to someembodiments, the flight of the transport screw may be made faster orslower, depending on the pitch of the threads of the transport screwelement. In a transport screw, a greater pitch (i.e., threads/per unitof length) will result in slower transport of the material, while alower pitch will result in faster transport of the material. Manydifferent varieties of transport screw elements may be used. In someembodiments, utilizing a twin screw extruder, each screw may containtransport screw elements that are intermeshed. While transport screwelements mix some composite material, the primary function is conveyingmaterials downstream in the extruder.

In some embodiments, the extruder may comprise one or more reverse screwelement 45. These are generally utilized to reverse the flow of thecomposite materials toward the feed end of the extruder. As such, areverse screw element 45 blocks the flow of components of the compositemixture, thus acting as a temporary seal and promotes added nblending ofthe components and dispersion of fillers and other additives. In someembodiments, such components of the composite mixture may pass thereverse screw element after another shearing force or pressure allowsthe components to pass the reverse screw element. In some embodiments,the reverse screw element allows for substantial mixing of filler andother polymer composite materials.

As shown in FIG. 2, a kneading block 25 is a screw element that includesa plurality of double-tipped kneading discs having a substantially ovalcross section and arranged in the axial direction of the screw shaft.Each kneading disc may be displaced from one another. In twin screwextruders, kneading discs of the first screw are kept staggered at about90 degrees to the corresponding kneading discs on the second screw. Analternative embodiment of kneading blocks may include the configurationof kneading block 40 as shown in FIG. 1. Kneading blocks typically havefrom about 4 to about 6 blades per screw element. Kneading blocks aretypically used to provide high shear stress and high mixing strengths,particularly when mixing solids with liquids (or melted plastics).Kneading blocks are generally self-wiping.

Lobal screw elements are generally a longer screw element. In someembodiments, a lobal screw element has 2 or 3 or more faces. In someembodiments, the lobal screw may be polygonal. Lobal screw elements donot comprise a plurality of discs like kneading blocks. Instead, lobalscrew elements are generally a single structure. However, lobal screwelements may have one or more axial twists. In some embodiments, theaxial twist of a lobal screw element is less than 180°. In someembodiments, the axial twist of a lobal screw element is less than 140°.In some embodiments, the axial twist of a lobal screw element is lessthan 90°. In some embodiments, the axial twist of a lobal screw elementis less than 45°. In some embodiments, the axial twist of a lobal screwelement is substantially 0°. One purpose of a lobal screw element is tosqueeze various composite material in a defined space. Such lobal screwelements cause very high shear in the defined area. It has beendiscovered that lobal screw elements may force liquids to mix intimatelywith one another. In additionally embodiments, lobal screw element canprovide substantial wetting of inorganic materials such as fibers andfillers by liquid components of the polymeric composite material, suchas melted resins or liquid monomers. Lobal screw elements may be neutralor forward moving elements. Lobal screw elements are typicallyself-wiping in a twin screw extruder configuration as shown in FIG. 3.

Slotted screw elements 55 may include a plurality of blades on all sidesof the screw elements. In some embodiments, the blades may be disposedin line with other blades, such as a transfer screw element with spacesor slots between the helically wound flight. However, there is norequirement for the blades to be uniform or to have positive pitch. Insome embodiments, a slotted screw blade includes angled ends. In someembodiments, the slotted screws have positive, negative, and neutralpitch (i.e., they may convey or block the composite material accordingto the type and arrangement of blades). However, some blades with anglesends may produce less conveying effect than a screw such as a transferscrew. In some embodiments, slotted screws are partially self-wiping. Insome embodiments, slotted screws are not self wiping in a twin screwarrangement. In some embodiments, the slots of the slotted screw elementmay be filled with one or more composite materials, such as a hardenedurethane. As a result, such slotted screw elements may producessubstantial amount of mixing of various components of the mixture andalso knead the mixture. In particular embodiments, slotted screws may beplaced toward the feed end of an extruder which allows slots not to fillwith polymeric resin, such as hardened polyurethane. Example of slottedscrew elements may be found in U.S. Pat. No. 6,136,246.

Advantageously, these screw elements may be used to produce a desiredamount of blending of components of the polymeric composite system. Incertain embodiments, each screw element defines a segment of theextruder. In some embodiments, the segments may have substantially thesame length. However, certain segments may have longer lengths thanother segments and segments may also contain more than one screwelement. In certain embodiments, the extruder may have up to nineextruder segments. However, the extruder may container more or lesssegments depending on the desired composite material characteristics. Insome embodiments, the extruder includes 1, 2, 3, 4, 5, 6, 7, 8, or 9segments.

Various segments of the extruder may be air or water cooled. Often,exothermic reactions during the production of the polymeric compositematerial may require sufficient cooling to prevent runaway exotherms.Such temperatures and cooling may be controlled by various means knownto persons having ordinary skill in the art.

One or more components of the polymeric composite material may beintroduced into one or more segments of the extruder through hoppers,feed chutes, or side feeders. One or more components may also be meteredinto the extruder through various means. Continuous feeding of therespective components of the polymeric composite material results in acontinuous process of extruding the polymeric composite material.

Depending on the exact arrangement of the screw elements, the segmentsmay further be classified into broader sections such as conveyingsections and mixing sections. For example, a first composite componentmay be introduced in a first segment having a first transport screw, anda second composite component may be introduced in a second segment havea second transport screw. If such first and second segments are adjacentto each other, then the first and second segment may be classified as aconveying section. However, classification as a conveying section doesnot preclude mixing, even intimate mixing, of the various components ofthe polymeric composite material.

Such composite components may then be further transferred into othersegments or sections. The components generally are transferred by thescrews from the feed end to the discharge end of the extruder. In oneembodiment, components are transferred into a mixing section. A mixingsection may include a kneading blocks or reverse screws. Reverse screwshave negative pitch. Thus, the reverse screws may block the materialsuntil sufficient shearing forces the various components of the compositematerial through this barrel segment. Generally, this results insubstantial mixing of the various components of the composite material.

It has been discovered that certain embodiments of extruders are able toproduce highly filled polyurethane composite materials. Variouscomponents of the polymer composite material may include one or more ofthe following: at least polyol, at least one monomer or oligomeric di-or poly-isocyanates, an inorganic filler, fibrous materials, at leastone catalyst, surfactants, colorants, and other various additive. Suchcomponents are further described herein.

Described herein are polymeric composite materials. In particularembodiments, the polymeric composite material include polyurethanecomposite materials. While the embodiments described herein arespecifically related to polyurethane composite materials, the technologymay also be applicable to many other polymeric resins, particularlythose related to highly filled thermosetting polymers. Generally, apolyurethane is any polymer consisting of a chain of organic unitsjoined by urethane linkages. Typically, a polyurethane may be formed byreaction of one or more monomeric or oligomeric poly- or di-isocyanates(sometimes referred to as “isocyanate”) and at least one polyol, such asa polyester polyol or a polyether polyol. These reactions may further becontrolled by various additives and reaction conditions. For example,one or more surfactants may be used to control cell structure and one ormore catalysts may be used to control reaction rates. Advantageously,the addition of certain polyol and isocyanate monomers and certainadditives (e.g., catalysts, crosslinkers, surfactants, blowing agents),may produce a polyurethane material that is suitable for commercialapplications.

As is well known to persons having ordinary skill in the art,polyurethane materials may also container other polymeric components byvirtue of side reactions of the polyol or isocyanate monomers. Forexample, a polyisocyanurate may be formed by the reaction of optionallyadded water and isocyanate. In addition, polyurea polymers may also beformed. In some embodiments, such additional polymer resins may have aneffect on the overall characteristics of the polyurethane compositematerial.

It has further been found that some portion of the polymeric componentof polyurethanes may be replaced with one or more fillers such asparticulate material and fibrous materials. With the addition of suchfillers, the polyurethane composite materials may still retain goodchemical and mechanical properties. These properties of the polyurethanecomposite material allows for its use in building materials and otherstructural applications. Advantageously, the polyurethane compositematerial may contain large loadings of filler content withoutsubstantially sacrificing the intrinsic structural, physical, andmechanical properties of the polymer. Such building materials would haveadvantages over composite materials made of less or no filler. Forexample, the building materials may be produced at substantiallydecreased cost. Furthermore, decreased complexity of the processchemistry may also lead to decreased capital investment in processequipment.

In one embodiment, the composite materials have a matrix of polymernetworks and dispersed phases of particulate or fibrous materials. Thepolymer matrix includes a polyurethane network formed by the reaction ofa poly- or di-isocyanate and one or more polyols. The matrix is filledwith a particulate phase, which can be selected from one or more of avariety of components, such as fly ash particles, axially orientedfibers, fabrics, chopped random fibers, mineral fibers, ground wasteglass, granite dust, slate dust or other solid waste materials.

Such polyurethane composite materials may be formed with a desireddensity, even when foamed, to provide structural stability and strength.In addition, the polyurethane composite materials can be easily tuned tomodify its properties by, e.g., adding oriented fibers to increaseflexural stiffness, or by adding pigment or dyes to hide the effects ofscratches. Also, such polyurethane composite materials may also beself-skinning, forming a tough, slightly porous layer that covers andprotects the more porous material beneath. Such tough, continuous,highly adherent skin provides excellent water and scratch resistance. Inaddition, as the skin is forming, an ornamental pattern (e.g., asimulated wood grain) can be impressed on it, increasing the commercialacceptability of products made from the composite.

Described herein are certain improvements that may be used in theproduction of polyurethane composite materials. Some previouslydescribed polyurethane composite material systems are included in U.S.patent application Ser. No. 10/764,012, filed Jan. 23, 2004, andentitled “FILLED POLYMER COMPOSITE AND SYNTHETIC BUILDING MATERIALCOMPOSITIONS,” now published as U.S. Patent Application Publication No.2005-163969-A1, and U.S. patent application Ser. No. 11/190,760, filedJul. 27, 2005, and entitled “COMPOSITE MATERIAL INCLUDING RIGID FOAMWITH INORGANIC FILLERS,” now published as U.S. Patent ApplicationPublication No. 2007-0027227 A1, which are both hereby incorporated byreference in their entireties. However, in now way, are suchpolyurethane composite material systems intended to limit the scope ofthe improvements described in the present application.

The various components and processes of preferred polyurethane compositematerials are further described herein:

Monomeric or Oligomeric Pol or Di-isocyanates

As discussed above, one of the monomeric components used to form apolyurethane polymer of the polyurethane composite material is one ormore monomeric or oligomeric poly or di-isocyanates. The polyurethane isformed by reacting a poly- or di-isocyanate. In some embodiments, anaromatic diisocyanate or polyisocyanate may be used.

In certain embodiments methylene diphenyl diisocyanate (MDI) is used.The MDI can be MDI monomer, MDI oligomer, or mixtures thereof. Theparticular MDI used can be selected based on the desired overallproperties, such as the amount of foaming, strength of bonding to theinorganic particulates, wetting of the inorganic particulates in thereaction mixture, strength of the resulting composite material, andstiffness (elastic modulus). Although toluene diisocyanate can be used,MDI is generally preferable due to its lower volatility and lowertoxicity. Other factors that influence the particular MDI or MDI mixtureare viscosity (a low viscosity is desirable from an ease of handlingstandpoint), cost, volatility, reactivity, and content of 2,4 isomer.Color may be a significant factor for some applications, but does notgenerally affect selection of an MDI for preparing an article.

Light stability is also not a particular concern for selecting MDI foruse in the composite material. According to some embodiments, thecomposite material allows the use of isocyanate mixtures not generallyregarded as suitable for outdoor use, because of their limited lightstability. When used in to form the polyurethane composite material,such materials surprisingly exhibit excellent light stability, withlittle or no yellowing or chalking. Suitable MDI compositions includethose having viscosities ranging from about 25 to about 200 cp at 25° C.and NCO contents ranging from about 30% to about 35%. Generally,isocyanates are used that provide at least 1 equivalent NCO group to 1equivalent OH group from the polyols, desirably with about 5% to about10% excess NCO groups. Useful polyisocyanates also may include aromaticpolyisocyanates. Suitable examples of aromatic polyisocyanates include4,4-diphenylmethane diisocyanate (methylene diphenyl diisocyanate), 2,4-or 2,6-toluene diisocyanate, including mixtures thereof, p-phenylenediisocyanate, tetramethylene and hexamethylene diisocyanates,4,4-dicyclohexylmethane diisocyanate, isophorone diisocyanate, mixturesof 4,4-phenylmethane diisocyanate and polymethylenepolyphenylisocyanate. In addition, triisocyanates such as,4,4,4-triphenylmethane triisocyanate 1,2,4-benzene triisocyanate;polymethylene polyphenyl polyisocyanate; and methylene polyphenylpolyisocyanate, may be used. Isocyanates are commercially available fromBayer USA, Inc. under the trademarks MONDUR and DESMODUR. Suitableisocyanates include Bayer MRS-4, Bayer MR Light, Dow PAPI 27, Bayer MR5,Bayer MRS-2, and Huntsman Rubinate 9415.

In certain embodiments, the average functionality of the isocyanatecomponent is between about 1.5 to about 4. In other embodiments, theaverage functionality of the isocyanate component is about 3. In otherembodiments, the average functionality of the isocyanate component isless than about 3, including, about 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,2.5, 2.6, 2.7, 2.8, and 2.9. In some embodiments, the isocyanate has afunctionality of about 2. Some of these embodiments produce polyurethanecomposite materials with higher mechanical strengths and lower coststhan polyurethane composite material comprising more than about 2.

As indicated above, the isocyanate used in the invention is reacted withone or more polyols. In general, the ratio of isocyanate to polyol(isocyanate index), based on equivalent weights (OH groups for polyolsand NCO groups for isocyanates) is generally in the range of about 0.5:1to about 1.5:1, more particularly from about 0.8:1 to about 1.1:1, andin another embodiment, from about 0.8:1 to about 1.2:1. Ratios in theseranges provide good foaming and bonding to inorganic particulates, andyields low water pickup, fiber bonding, heat distortion resistance, andcreep resistance properties. However, precise selection of the desiredratio will be affected by the amount of water in the system, includingwater added per se as a foaming agent, and water introduced with othercomponents as an “impurity.”

In some embodiments, an isocyanate may be selected to provide a reducedisocyanate index. It has been discovered that the isocyanate index canbe reduced without compromising the polyurethane composite material'schemical or mechanical properties. It is additionally advantageousaccording to some embodiments to use an isocyanate with a reducedisocyanate index as isocyanates are generally higher priced thanpolyols. Thus, a polyurethane system formed by an isocyanate monomerwith a reduced isocyanate index may result in reduced cost of producingthe total system.

Polyols

According to some embodiments, the polyurethane polymer is a reactionproduct of one or more polyols with an isocyanate. The one or morepolyols used may be single monomers, oligomers, or blends. Mixtures ofpolyols can be used to influence or control the properties of theresulting polymer network and composite material. The properties,amounts, and number of polyols used may be varied to produce a desiredpolyurethane composite material.

It is generally desirable to use polyols in liquid form, and generallyin the lowest viscosity liquid form available, as these can be moreeasily mixed with the inorganic particulate material. So-called “EO”tipped polyols can be used; however their use is generally avoided whereit is desired to avoid “frosting” of the polymer material when exposedto water.

In some embodiments, the at least one polyol include a polyester orpolyether polyol. Polyether polyols are commercially available from, forexample, Bayer Corporation under the trademark MULTRANOL. In general,desirable polyols include polyether polyols, such as MULTRANOL (Bayer),including MULTRANOL 3400 or MULTRANOL 4035, ethylene glycol,polypropylene glycol, polyethylene glycol, diethylene glycol,triethylene glycol, dipropylene glycol, glycerol, 2-pentane diol,pentaerythritol adducts, 1trimethylolpropane adducts, trimethylolethaneadducts, ethylendiamine adducts, and diethylenetriamine adducts,2-butyn-1,4-diol, neopentyl glycol, 1,2-propanediol, pentaerythritol,mannitol, 1,6-hexanediol, 1,3-buytylene glycol, hydrogenated bisphenolA, polytetramethyleneglycolethers, polythioethers, and other di- andmulti-functional polyethers and polyester polyethers, and mixturesthereof. The polyols need not be miscible, but should not causecompatibility problems in the polymeric composite.

In some embodiments, plant-based polyols are used as at least onepolyol. These polyols are lower in cost, and not dependent on the priceand availability of petroleum. In some embodiments, the plant-basedpolyols provide a polyurethane system that is substantially identical tothat provided by oil-based polyols. In other embodiments, plant-basedpolyols can be used to replace at least a portion of the oil-basedpolyols. By employing plant-based polyols, the polyurethane compositematerial is more environmentally safe and friendly. In addition, certainequipment used to handle and dispose of oil-based polyols may be costly.

In some embodiments, the at least one polyol is a polyester polyol thatis substantially resistant to water soaking and swelling. Thus, thesepolyols can be used in the formation of polyurethane composite materialswhich, when cured, attracts less water. In certain cases, the polyesterpolyols absorb less water than polyether polyols. However, in someembodiments, polyester polyols and polyether polyols can be mixed in theformation of polyurethane composite material to provide better waterresistance.

Some embodiments of the polyurethane composite material comprise atleast one polycarbonate polyol. These embodiments provide higher impactand/or chemical resistance, as compared to polyurethane compositematerial made from polyester and/or polyether polyols. However,combinations of polycarbonate polyols, polyester polyols, and polyetherpolyols can be used in systems with high inorganic fillers to providethe desired mechanical and physical property of the polyurethanecomposite material. In some embodiments, building products comprisingthe polyurethane composite materials which employ at least one polyesterpolyol demonstrate improved water resistance.

In some embodiments, at least some phenolic polyols are used to makepolyurethane composite materials which have improved flame retardancy ascompared to those polyurethane composite materials that are not madefrom phenolic polyols. Such polyurethane composite materials may also befire and smoke resistance.

In other embodiments, the polyurethane composite materials are made fromat least one acrylic polyol. In some embodiments, the polyurethanecomposite materials made from the at least one acrylic polyoldemonstrate improved weathering as compared to those that are not madefrom at least one acrylic polyol. In other embodiments, the polyurethanecomposite materials are made from at least one acrylic polyol exhibitsubstantially no discoloration when exposed to sunlight.

In one embodiment, a first polyol having a first hydroxyl number and asecond polyol having a second hydroxyl number less than the firsthydroxyl number may be used. Such combination of polyols form a firstpolyurethane that is less rigid than a second polyurethane that would beformed by the reaction of the first polyol in the absence of the secondpolyol. In some embodiments, the first polyol has a hydroxyl numberranging from about 250 to about 500 mg KOH/g. In some embodiments, thefirst polyol has a hydroxyl number ranging from about 300 to about 450mg KOH/g. In some embodiments, the first polyol has a hydroxyl numberranging from about 320 to about 400 mg KOH/g. In some embodiments, thefirst polyol has a hydroxyl number ranging from about 350 to about 500mg KOH/g. In some embodiments, the first polyol has a hydroxyl numberranging from about 370 to about 600 mg KOH/g. In some embodiments, thesecond polyol has a hydroxyl number less than the first polyol. In someembodiments, the second polyol has a hydroxyl number ranging from about20 to about 120 mg KOH/g. In some embodiments, the second polyol has ahydroxyl number ranging from about 20 to about 70 mg KOH/g. In someembodiments, the second polyol has a hydroxyl number ranging from about30 to about 60 mg KOH/g. In some embodiments, the second polyol has ahydroxyl number ranging from about 50 to about 75 mg KOH/g. In someembodiments, the second polyol has a hydroxyl number ranging from about40 to about 60 mg KOH/g. In some embodiments, the second polyol has ahydroxyl number ranging from about 30 to about 50 mg KOH/g.

For example, a first polyol such as Bayer's MULTRANOL 4500 may be usedin combination with Bayer's ARCOL LG-56 and MULTRANOL 3900. In thiscase, the first polyol has a hydroxyl number ranging from 365-395 mgKOH/g. For ARCOL LG-56, the second polyol has a hydroxyl number rangingfrom 56.2 to 59.0 mg KOH/g. For MULTRANOL 3900 has a hydroxyl numberranging from 33.8 to 37.2 mg KOH/g. However, these examples are notintended to be limiting. Any number of polyol as described above may beselected for the hydroxyl number in controlling the flexibility orrigidity of a polyurethane product.

In one embodiment, mixture of polyols can be used to achieve the desiredmechanical strength and rigidity of the final polyurethane compositematerial. In some embodiments, polyols with OH functionality betweenabout 2 to about 7 can be used. In other embodiments, the averagefunctionality of the polyols is between about 4 to about 7. Thepolyurethane composite materials become less expensive because theamount of isocyanate needed to react with the polyols to substantiallyform the desired polyurethane decreases. While this in some case mayincrease the rubberiness, non-brittleness, or flexibility of thepolyurethane composite material, the correct balance of these functionalpolyols with OH functionality, between about 4 to about 8, maintains themechanical properties of the polyurethane composite material, ascompared to a polyurethane composite material made from polyols with anaverage functionality less than 4.

In some embodiments, the polyurethane composite material is made byusing higher functional polyols in place of polyols having an averagefunctionality of 2 or 3. In these embodiments, the polyurethanecomposite material has more cross linking. Some embodiments have higherimpact strength, flexural strength, flexural modulus, chemicalresistance, and water resistance as compared to the polyurethanecomposite material formed by polyols having a functionality of about 2to about 3.

In some embodiments, the polyurethane composite material is made byusing more than one polyol with different OH numbers to give the sameweighted average OH number. Such polyurethane composite materials yielda more segmented polymer. By allowing many polyols of differentfunctionality and/or molecular weight to be mixed together to make theneeded OH number to balance the number of isocyanate groups, theorderliness of the resulting polymer chain is more segmented and lesslikely to align together. In some embodiments, the polyurethanecomposite material comprises three, four, five, or six types of polyolsof different functionality and/or molecular weight. For example, apolyurethane system can be made from combination of multiple types ofpolyols, wherein at least one first polyol has an average functionalityof about 2, wherein at least one second polyol has an averagefunctionality of about 4, and wherein at least one third polyol has anaverage functionality of about 6. In one embodiment, the overall numberof hydroxyl groups may be adjusted with varying polyols. In someembodiments, combinations of polyols with great number of hydroxylgroups may be blended with smaller quantities of polyols with lesshydroxyl groups in order to produce a desired overall number of hydroxylgroups, which will react with the isocyanate.

In some embodiments, impact strength of the polyurethane compositematerial is greater than polyurethane composite materials comprisingpolyols of the same or substantially similar functionality and/ormolecular weight. Although the two polyurethane compositions maycomprise polyols with substantially similar average functionality and/ormolecular weight, the polyurethane composition comprising polyols withsubstantially different functionality may exhibit improved mechanicalproperties such as impact strength. In some embodiments, polyurethanecomposite materials comprising polyols of multiple functionalities aremore resistant to stress cracking.

Other embodiments of the polyurethane composite material are made fromat least one polyol with a molecular weight from about 2000 to about8000. These polyurethane composite materials exhibit an integral skin.In some embodiments, the skin is thicker. In other embodiments, the skinis less porous and harder. In some embodiments, the use of at least onepolyol with a molecular weight from about 2000 to about 8000 results inthe migration of the at least one polyol to migrate to the outer surfaceof the polyurethane composite material, thus allowing more outer skin tobe formed.

In one embodiment, mixtures of two or more polyols may be used. In someembodiments, each polyol of a multi-polyol polyurethane system may bechosen for the various mechanical and chemical properties that result inthe polyurethane composite produced as a result of using the polyol. Forexample, it is known to persons having ordinary skill in the art thatpolyols are often classified as rigid or flexible polyols based onvarious properties of the individual polyol and the overall flexibilityof a polyurethane polymer produced from the respective polyols.Typically, the rigidity or flexibility of the polyurethane formed fromany single polyol may be governed by one or more of the hydroxyl number,functionality, and molecular weight of the polyol. As such, one or morepolyols with different characteristics may be used to control thephysical and mechanical characteristics of the polyurethane compositematerial.

In one embodiment, the amount of rigid polyol is carefully controlled inorder to avoid making the composite too brittle. In some embodiments,the weight ratio of rigid to flexible polyol ranges from about 0.5 toabout 20. In other embodiments, the ratio of rigid to flexible polyol isabout 1 to about 15. In other embodiments, the ratio of rigid toflexible polyol is about 4 to about 15. In other embodiments, the ratioof rigid to flexible polyol is about 3 to about 10. In otherembodiments, the ratio of rigid to flexible polyol is about 6 to about12.

If more than one polyol is used to form the polyurethane composition,mixtures of polyols can be used. In certain embodiments, thepolyurethane is formed by reaction of a first polyol and a secondpolyol. In some of these embodiments, the first polyols has afunctionality of at least three and a hydroxyl number of about 250 toabout 800, and more preferably about 300 to about 400. In someembodiments, the first polyol hydroxyl number is about 350 to about 410.In some of these embodiments, the molecular weight of the first polyolranges from about 200 to about 1000. In other embodiments, the molecularweight of the first polyol ranges from about 300 to about 600. In otherembodiments, the molecular weight of the first polyol ranges from about400 to about 500. Still, in some embodiments, the molecular weight ofthe first polyol is about 440.

A second polyol can be used which produces a less rigid polyurethanecompared to a polyurethane produced if only the first polyol is used. Insome embodiments, the second polyol has a functionality of about 3. Insome embodiments, the functionality of the second polyol is not greaterthan three. In these embodiments, the second polyol can have a molecularweight of about 1000 to about 6000. In other embodiments, the secondpolyol has a molecular weight of about 2500 to about 5000. In someembodiments, the second polyol has a molecular weight of about 3500 toabout 5000. In some embodiments, the molecular weight is about 4800. Inother embodiments, the molecular weight of the second polyol is about3000. In some of these embodiments, the second polyol has a hydroxylnumber of about 25 to about 70, and more preferably about 50 to about60.

Fillers

As discussed above, one or more filler materials may be included in thepolyurethane composite material. In some embodiments, it is generallydesirable to use particulate materials with a broad particle sizedistribution, because this provides better particulate packing, leadingto increased density and decreased resin level per unit weight ofcomposite. Since the inorganic particulate is typically some form ofwaste or scrap material, this leads to decreased raw material cost aswell. In certain embodiments, particles having size distributionsranging from about 0.0625 inches to below 325 mesh have been found to beparticularly suitable. In other embodiments, particles having sizedistribution range from about 5 μm to about 200 μm, and in anotherembodiment, from about 20 μm to about 50 μm.

Suitable inorganic particulates can include ground glass particles, flyash, bottom ash, sand, granite dust, slate dust, and the like, as wellas mixtures of these. Fly ash is desirable because it is uniform inconsistency, contains some carbon (which can provide some desirableweathering properties to the product due to the inclusion of fine carbonparticles which are known to provide weathering protection to plastics,and the effect of opaque ash particles which block UV light, andcontains some metallic species, such as metal oxides, which are believedto provide additional catalysis of the polymerization reactions. Groundglass (such as window or bottle glass) absorbs less resin, decreasingthe cost of the composite.

In general, fly ash having very low bulk density (e.g., less than about40 lb/ft³) and/or high carbon contents (e.g., around 20 wt % or higher)are less suitable, since they are more difficult to incorporate into theresin system, and may require additional inorganic fillers that havemuch less carbon, such as foundry sand, to be added. Fly ash produced bycoal-fueled power plants, including Houston Lighting and Power powerplants, fly and bottom ash from Southern California Edison plants(Navajo or Mohave), fly ash from Scottish Power/Jim Bridger power plantin Wyoming, and fly ash from Central Hudson Power plant have been foundto be suitable for use in the invention.

Some embodiments of the polyurethane composite materials additionallycomprise blends of various fillers. In some of these embodiments, thepolyurethane composite materials exhibit better mechanical such asimpact strength, flexural modulus, and flexural strength. One advantagein using blends of such systems is higher packing ability of blends offillers. For example, a 1:1 mixture of coal fly ash and bottom ash hasalso been found to be suitable as the inorganic particulate composition.

Example in Table 1: The examples below were all mixed in a thermosetaromatic polyurethane system made with Hehr 1468 polyether polyol (15%of the total weight of the non-ash portion), water (0.2%), Air ProductsDC-197 (1.5%), Air Products 33LV amine catalyst (0.06%), Witco FomrezUL28 tin catalyst (0.02%), and Hehr 1426A isocyanate (15%). 1.5×3.5×24inch boards were made.

TABLE 1 Ash % by Weight of Total Flexural Flexural Resin Density,strength, Modulus, Coal Ash Type System lbs/cu ft psi Ksi Mohave bottomash 65% 70 1911 421 Mohave bottom ash + 65% 74 2349 466 Mohave fly ash(50/50) Mohave bottom ash 75% 68 930 266 Mohave bottom ash + 75% 79 2407644 Mohave fly ash (50/50) Navajo bottom ash 65% 69 2092 525 Navajobottom ash + Navajo 65% 74 2540 404 fly ash (50/50) Navajo bottom ash75% 70 1223 377 Navajo bottom ash + Navajo 75% 84 2662 691 fly ash(50/50)

Thus, embodiments of the polyurethane composite material which comprisebottom and fly ash exhibit increased flexural strength and flexuralmodules as compared to polyurethane composite material comprising bottomash alone. Some of these embodiments have a density of about 65 lbs/ft³to about 85 lbs/ft³, including about 65, 67, 69, 71, 73, 75, 77, 79, 81,83, or 85 lbs/ft³.

In some of embodiments, the polyurethane composite material comprisingabout 65% ash filler of which about 32.5 wt % was bottom ash and about32.5% was fly ash had a flexural strength of at least about 2300 psi,more preferably at least about 2400 psi, and even more preferably atleast about 2500 psi. In some of embodiments, the polyurethane compositematerial comprising about 75% ash filler of which about 37.5 wt % wasbottom ash and about 37.5% was fly ash had a flexural strength of atleast about 2400 psi, more preferably at least about 2500 psi, and evenmore preferably at least about 2650 psi.

In some of embodiments, the polyurethane composite material comprisingabout 65% ash filler of which about 32.5 wt % was bottom ash and about32.5% was fly ash had a flexural modulus of at least about 400 Ksi, morepreferably at least about 440 Ksi, and even more preferably at leastabout 460 Ksi. In some of embodiments, the polyurethane compositematerial comprising about 75% ash filler of which about 37.5 wt % wasbottom ash and about 37.5% was fly ash had a flexural modulus of atleast about 640 Ksi, more preferably at least about 660 Ksi, and evenmore preferably at least about 690 Ksi.

In some embodiments, slate dust can be added to the polyurethanecomposite material to provide UV protection to the polyurethanecomposite material. Some of these embodiments additionally comprise oneor more of pigments, light stabilizers, and combinations thereof. Insome embodiments, polyurethane composite materials comprising slate dustexhibit substantially improved weathering. In some embodiments, thepolyurethane composite material comprises a dust. A dust may be selectedfrom at least one of slate dust, granite dust, marble dust, otherstone-based dusts, and combinations thereof. In some embodiments, thepolyurethane composite material comprises about 0.2 to about 70 wt %dust. In other embodiments, the polyurethane composite materialscomprise about 10 to about 50 wt % of dust. In other embodiments, thepolyurethane composite materials comprise about 20 to about 60 wt % ofdust. In other embodiments, the polyurethane composite materialscomprise about 30 to about 55 wt % of dust. In some embodiments, dustmay be added to the composite material as additional filler. In thisembodiment, the filler that is not dust may be present in the compositein amounts from about 10 to about 70 weight percent and the dust may beadded in amounts of about 5 to about 35 weight percent.

The following is an example of a polyurethane composite material thatcomprises dust. The example should be in no way limiting, as otherembodiments will be readily understood by a person having ordinary skillin the art.

Example from Table 2: In a blend of Cook Composites 5180 MDI (13.1% byweight), 5205 polyol (3.91%), Dow DER (1.98%), antimony trioxide flameretardant (3.52%), with Air Products DC-197 silicone surfactant (0.23%),benzoyl peroxide (0.55%), and chipped slate (59.5%), with the addedpigments, carbon black and slate dust, all acting as UV inhibitors. Thelight exposure was to a high fusion (UV light) chamber at AlliedSignalAerospace. Usually a 10 minute exposure in this chamber would deeplydiscolor this resin system due to the yellowing of the MDI-basedingredients in the resin system.

TABLE 2 Sample # Red Iron Green Chromium Carbon Time for Slight Change(Numbers are Oxide Pigment, Oxide Pigment, Black, in Sheen or Slightpurposely not Coal Fly Slate Cardinal Cardinal Chroma- Discoloration, inorder) Ash Dust Color Co. Color Co. Tek Co. minutes 1 16.7% — 10 2 16.7%— 0.58% 10 3 16.6% — 0.58% 10 4 16.7% — 0.58% 10 5 — 16.6% 20 7 — 16.6%0.58% 20 8 — 16.6% 0.58% 20 6 — 16.6% 0.58% 20+ (Test Ended)

In the above test, clearly slate dust provided better light stabilitythan coal ash, and the combination of slate dust plus carbon blackprovided the best UV resistance, and had not failed yet in the 20 minutetest (the only sample to not fail). The effect of the slate dust was farmore influential for UV stability then the various pigments tested,including carbon black plus fly ash.

In some embodiments, the polyurethane composite material compositioncomprises about 20 to about 95 weight percent of inorganic filler, whichincludes, for example, approximately 20, 25, 30, 35, 40, 42, 44, 46, 48,50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84,86, 88, 90, 92, or 94 weight percent of filler. These amounts may bebased on the total of all of the fillers, such as one or more of flyash, dust, and fibrous material. However, the filler values may also berepresentative of only one type of filler, e.g, fly ash. In certainembodiments, the polymeric composite material may contain the filler inan amount within a range formed by the two of the foregoing approximateweight percent. In other embodiments, the polyurethane compositematerial comprises about 40 to about 85 weight percent of the filler. Inother embodiments, the polyurethane composite material comprises about55 to about 80 weight percent of the filler. In other embodiments, thepolyurethane composite material comprises about 65 to about 85 weightpercent of the filler. In other embodiments, the polyurethane compositematerial comprises about 40 to about 60 weight percent of the filler. Inother embodiments, the polyurethane composite material comprises about55 to about 70 weight percent of the filler. Here, the unit “weightpercent” refers to the relative weight of the filler component comparedto the total weight of the composite material.

Fibers

In some embodiments, reinforcing fibers can also be introduced into thepolyol mixture prior to introduction of the isocyanate. In someembodiments, reinforcing fibers may be introduced after the at least onepolyol and the isocyanate are mixed. These can include fibers per se,such as chopped fiberglass (chopped before or during mixing process suchas extrusion), or fabrics or portions of fabrics, such as rovings orlinear tows, or combinations of these. Typically, the reinforcing fibersrange from about 0.125 in. to about 1 in, more particularly from about0.25 in to about 0.5 in. The reinforcing fibers give the material addedstrength (flexural, tensile, and compressive), increase its stiffness,and provide increased toughness (impact strength or resistance tobrittle fracture). Fabrics, rovings, or tows increase flexural stiffnessand creep resistance. The inclusion of the particular polyurethanenetworks of the invention, together with the optional surfactants, andthe inorganic particulate sizes used make the composite of the inventionparticularly and surprisingly well suited for inclusion of reinforcingfibers in foamed material, which normally would be expected to ruptureor distort the foam bubbles and decrease the strength of the compositesystem.

In addition to inclusion of reinforcing fibers into the polyol mixtureprior to polymerization, oriented axial fibers can also be introducedinto the composite after extrusion, as the polymer exits the extruderand prior to any molding. The fibers (e.g., glass strings) can desirablybe wetted with a mixture of polyol (typically a higher molecular weight,rigid polyol) and isocyanate, but without catalyst or with a slow curecatalyst, or with other rigid or thermosetting resins, such as epoxies.This allows the wetted fiber to be incorporated into the compositebefore the newly added materials can cure, and allows this curing to bedriven by the exotherm of the already curing polymer in the bulkmaterial.

Whether added before or after polymerization and/or other mixingprocessing such as extrusion, the dispersed reinforcing fibers may bebonded to the polymeric matrix phase, thereby increasing the strengthand stiffness of the resulting material. This enables the material to beused as a structural synthetic lumber, even at relatively low densities(e.g., about 20 to about 60 lb/ft³).

According to certain embodiments, many types of fibers may be suitablefor use in the polyurethane composite material. In some embodiments, thepolyurethane composite materials comprise at least one of basalt,Wollastinite, other mineral fibers, or combinations thereof. In someembodiments, these components may be used in place of or in combinationwith glass fibers

Example from Table 3: In a mixture of Hehr 1468 polyether polyol (500grams), Hehr 1468 MDI (432 g), water (3 g), Air Products 33LV aminecatalyst (1 g), Mohave coal fly ash (800 g), and the followingreinforcing fibers, all made in 1.5×3.5×24 inch lumber samples:

TABLE 3 Flexural Flexural Fiber Strength, Modulus, Added psi Ksi None —1239 68 ¼ inch long 1% 1587 92 chopped fiberglass ¼ inch long 2.5%  1436 91 chopped fiberglass ¼ inch long 5% 1887 125 chopped fiberglass ¼inch long chopped fiberglass ¼ inch long 1% 2241 97 chopped basalt fiber¼ inch long 2.5%   2646 131 chopped basalt fiber ¼ inch long 5% 3516 174chopped basalt fiber ¼ inch long chopped basalt fiber Fiberglass +basalt 2.5%   2732 135 (1.25% each)

In some embodiments, basalt fibers provide more flexural strength, andflexural modulus to the highly-filled polyurethane composite materialsthan fiberglass, and the combination of the two fibers gives asynergistic effect on both measured properties.

In some of embodiments, the polyurethane composite material comprisingabout 1.25% of chopped fiber glass and about 1.25% of basalt had aflexural strength of at least about 2650 psi, more preferably at leastabout 2700 psi, and even more preferably at least about 2730 psi.

Axial fibers or fabrics can also be added to the polyurethane compositematerial. These fiber and/or fabric typically increase the rigidity ofthe polyurethane composite material, and increase the mechanicalstrength. Using thicker fibers, rovings, tows, fabrics or rebar in theaxial or stressed direction of the product can eliminate or reduce thetendency of the plastic to creep with time or higher temperature. Thesereinforcements also give higher initial tensile and flexural strength,and higher flexural and tensile stiffness of the polyurethane compositematerial. One advantage of using axial fibers or fabrics is that thefibers or fabrics are oriented in a direction that supports thepolyurethane composite material. Unlike axial fibers, randomly choppedfibers are less structurally supportive.

In some embodiments, the axial fibers or fabrics may be added while dry(no resin on them). In other embodiments, the fibers or fabrics may be“wet” with resin when mixed with the polyurethane composite material. Insome embodiments, the axial fibers or fabrics are added to the polyoland catalyst premix. In other embodiments, the axial fibers or fabricsare added to the isocyanate premix. Still, other embodiment may includeadding the axial fibers of fabric together with a slow or delayedreaction polyol, catalyst, and isocyanate. Thus, the axial fibers can beadded with multiple components of the polyurethane composite material.

In some embodiments, the axial fibers or fabrics may be added to thepolyurethane composite material under tension, as is done with steelrebar in structural concrete. This provides additional strength in thetension direction, and in bending, as well as higher stiffness in thetension and bending directions.

Example in Table 4: Glass and basalt fibers were implanted in ahighly-filled coal ash-thermosetting polyurethane mixture while stilluncured, and the fibers laid lengthwise down the urethane in a box mold,and only on the top of the board (on one face). The fibers were laid inthe urethane mixture about ⅛ inch below the surface of the mix, butfrequently the fibers moved during the subsequent foaming and cure inthe closed box mold, and sometimes showed on the board surface.

The flexural properties were unaffected by this fiber movement. Theglass fibers from rovings were 0.755 g/ft, the basalt rovings fromAhlstrom (Canada) were 0.193 g/ft. The boards were 1.5×3.5×24 inches.During flexural testing the boards were tested so that the rovings wereon the tensile side of the boards (not the compression side). Some ofthe rovings were pre-wetted with the same resin system as in the boards,but without the coal ash filler. The resin system was: Bayer Multranol4035 polyether polyol (16.6% by weight), Bayer Multranol 3900 polyetherpolyol (5.5%), Air products DC-197 silicone surfactant (0.16%), water(0.07%), Witco Fomrez UL-28 tin catalyst (0.03%), Air Products 33LVamine catalyst (0.10%), Coal fly ash (49%), Bayer MRS4 MDI isocyanate(20.4%).

TABLE 4 Number of Rovings Inserted Total % Fiber Board Flexural Flexuralin Board, on 1 face, on Board Density, Strength, Modulus, Fiber Typespread evenly on face Wetted with Resin? Weight lbs/cu ft psi Ksi None(Resin Alone) — — — 45 1319 82 Glass 10 No 0.77% 32 2717 37 Glass: 10Yes 1.43% 36 3533 77 Glass 10 Yes, but pre-cured 0.73% 58 4000 188 Glass20 Yes 2.72% 35 4356 84 Basalt fiber 10 No 0.26% 41 1191 73 ″ 40 No0.79% 49 2465 96

By wetting the glass fibers with uncured resin or cured resin, theboards are considerably stronger—even stronger than basalt reinforcedboards with the same weight of fiber. By wetting the glass roving withpolyurethane resin, the strength of the glass roving exceeds that of theunwetted basalt fiber.

In some embodiments, polyurethane composite materials comprising lessthan about 1.5 wt % of glass fiber rovings prewet with resin had aflexural strength of at least about 3500 psi and more preferably atleast about 4000 psi. In embodiments wherein the prewet glass fiberrovings were procured with the polyurethane resin, the flexural strengthwas at least about 150 Ksi, and more preferably at least about 180 Ksi.

Chain Extenders & Cross Linkers

In some embodiments of the polyurethane composite material, lowmolecular weight reactants such as chain extenders or cross linkersprovide a more polar area in the polyurethane composite material. Thesereactants allow the polyurethane system to more readily bind theinorganic filler and/or inorganic or organic fibers in the polyurethanecomposite material.

In some embodiments, the polyurethane composite material comprises oneor more selected from chain extenders, crosslinkers, and combinationsthereof. In some embodiments, the chain extenders can be selected one ormore from the group comprising ethylene glycol, glycerin, 1,4-butanediol, trimethylolpropane, glycerol, or sorbitol. In some embodiments, atleast one cross linker may be used to replace at least a portion of theat least one polyol in the polyurethane composite material. In somecases, this results in reduced costs of the overall product.

In some embodiments which comprise chain extenders, the mechanicalproperties of the polyurethane composite material are improved. In someembodiments, chain extenders are not blocked from reacting with theisocyanate by the filler. This is due to the molecular size of the chainextenders. In some embodiments, the chain extenders result in bettermechanical properties as compared to polyurethane composite materialswith high filler inorganic loads, which do not use chain extenders.These mechanical properties include flexural strength and modulus,impact strength, surface hardness, and scratch resistance.

In other embodiments, polyurethane composite material comprising chainextenders traps metals and metal oxides. This is advantageous in highlyfilled polyurethane composite materials when the filler is coal or otherashes, including fly ash and bottom ash, which can contain hazardousheavy metals. In some embodiments, the polyurethane composite materialsubstantially prevents leaching of heavy metals in the polyurethanecomposite material.

In some embodiments, a highly filled polymer composition comprisingchain extenders provides faster curing and less need for post-curing ofthe polyurethane composite materials. In some embodiments, the chainextenders provide better water resistance for the polyurethane compositematerial. These chain extenders include diamine chain extenders, such asMBOCA and DETDA. However, other embodiments of the polyurethanecomposite material may comprise glycol extenders.

Blowing Agents

Foaming agent may also be added to the reaction mixture if a foamedproduct is desired. While these may include organic blowing agents, suchas halogenated hydrocarbons, hexanes, and other materials that vaporizewhen heated by the polyol-isocyanate reaction, it has been found thatwater is much less expensive, and reacts with isocyanate to yield CO₂,which is inert, safe, and need not be scrubbed from the process. Inaddition, CO₂ provides the type of polyurethane cells desirable in afoamed product (i.e., mostly closed, but some open cells), is highlycompatible with the use of most inorganic particulate fillers,particularly at high filler levels, and is compatible with the use ofreinforcing fibers.

If water is not added to the composition, some foaming may still occurdue to the presence of small quantities of water (around 0.2 wt %, basedon the total weight of the reaction mixture) introduced with the othercomponents as an “impurity.” Such water-based impurities may be removedby drying of the components prior to blending. On the other hand,excessive foaming resulting from the addition of too much water (eitherdirectly or through the introduction of “wet” reactants or inorganicparticulate materials) can be controlled by addition of an absorbent,such as UOP “T” powder.

The amount of water present in the system will have an important effecton the density of the resulting composite material. This amountgenerally ranges from about 0.10 wt % to about 0.40 wt %, based on theweight of polyol added, for composite densities ranging from about 20lb/ft³ to about 90 lb/ft³. However, polyurethane composite materialdensities may be controlled by varying one or more other components aswell. In some embodiments, the overall density of the polyurethanecomposite material may range from about 30 lb/ft³ to about 80 lb/ft³. Insome embodiments, the overall density of the polyurethane compositematerial may range from about 40 lb/ft³ to about 60 lb/ft³.

In some embodiments, the addition of excess blowing agent or water abovewhat is needed to complete the foam reaction adds strength and stiffnessto the polyurethane composite material, if the material is restrainedduring the forming of the composite material. Typically, excess blowingagent may be added to the polyol premixture. Such excessive blowingagent may produce a vigorously foaming reaction product. To contain suchreaction product, a forming device that contains the pressure orrestrains the materials from expanding may be used. Such forming devicesare further described herein. The restraint of the material or thehigher pressure created by a mold or restraining forming belts, causeshigher pressure within the material which modifies the foam cellstructure, thus allowing higher mechanical properties of the resultingcured material.

According to certain embodiments, use of excess blowing agent information of the polyurethane composite material may also improves thewater resistance of the polyurethane composite material. In someembodiments, use of excessive blowing agent may also increase thethickness and durability of the outer skin of the self skinningpolyurethane composite material.

Solvents

The addition of solvents to the reaction mixture may also providecertain advantages. In some embodiments of the polyurethane compositematerials, solvents can be added to the polyol premix prior to or duringthe formation of the polyurethane. While it is described that solventsare added to the polyol premix, solvents may also be added at otherstages of mixing of various components of the polyurethane compositematerial. In some embodiments, the solvent may be added with any one ormore components of the reaction mixture which produces the polyurethanecomposite material.

In some embodiments, addition of a solvent to a polyol premix results ina polyurethane composite material that is more scratch and marresistance as compared to the same polyurethane composition made withoutthe solvent added to the polyol premix. Additional properties thatresult in some embodiments include a harder skin. In addition, solventsmay cause a higher concentration of resin material to be in the selfskinning layer, as opposed to the fillers and reinforcing fibers. Insome materials, this provides a polyurethane composite material having ahigher concentration of ultraviolet stabilizers, antioxidants, and otheradditives are closer to the outside of the composite material. In someembodiments, use of solvent produces a polyurethane composite materialwith an increases skin thickness. In other embodiments, the skin densitymay also be increased. Still, in other embodiments, the addition ofsolvents may decrease the interior density of the polyurethane compositematerial.

In some embodiments, the addition of solvent to the polyol premixsubstantially improves the weathering of the polyurethane compositematerial due to the higher density and thickness of the outer skin,which can contain more concentrated antioxidants, pigments, fillers andUV inhibitors. In other embodiments, the addition of the solvent to thepolyol premix substantially prevents discoloration of the polyurethanecomposite material when a sample of the material is exposed to sunlightor UV radiation. In other embodiments, the addition of the solvent tothe polyol premix provides a polyurethane composite material (uponmixing of the rest of the components) which has improved anti-staticproperties.

For example, the addition of about 2 to about 10 wt % of a solventselected from the group consisting of a hydrocarbon solvent (pentane,hexane), carbon tetrachloride, trichloroethylene, methylene chloride,chloroform, methyl chloroform, perchloroethylene, or ethyl acetate to apolyol premix, the resulting self-skinning polyurethane compositematerial has a thicker skin as compared to polyurethane compositematerials which are not create by the addition of a solvent to thepolyol premix. As a result, the outer skin is much thicker, includinggreater than about 100, 200, 500, and about 1500% thicker as compared toa polyurethane made without adding solvent to the polyol premix. In someembodiments, the polyurethane composite material made by the addition ofsolvent to the polyol premix may have an increase outer density skin,thus making the skin harder, where the skin is greater than about 50, 75and about 150% harder as compared to a polyurethane made without addingthe solvent to the polyol premix. Furthermore, some embodiments of thepolyurethane composite material have an interior density that is lessthan between about 10 and about 50% as compared as compared to apolyurethane made without adding the solvent to the polyol.

Additional Components

The polyurethane composite materials can contain one or more compoundsor polymers in addition to the foregoing components. Additionalcomponents or additives may be added to provide additional properties orcharacteristics to the composition or to modify existing properties(such as mechanical strength or heat deflection temperature) of thecomposition. For example, the polyurethane composite material mayfurther include a heat stabilizer, an anti-oxidant, an ultravioletabsorbing agent, a light stabilizer, a flame retardant, a lubricant, apigment and/or dye. One having ordinary skill in the art will appreciatethat various additives may be added to the polymer compositionsaccording to embodiments of the invention. Some of these additionaladditives are further described herein.

UV Light Stabilizers, Antioxidants, Pigments

Ultraviolet light stabilizers, such as UV absorbers, can be added to thepolyurethane composite material prior to or during its formation.Hindered amine type stabilizers, and opaque pigments like carbon blackpowder, can greatly increase the light stability of plastics andcoatings. In some embodiments, phenolic antioxidants are provided. Theseantioxidants provide increased UV protection, as well as thermaloxidation protection.

In some embodiments, the polyurethane composite material comprises oneor more selected from the group consisting of light stabilizers andantioxidants. In combination, the light stabilizers and antioxidantsprovide a synergistic effect of reducing the detrimental effects of UVlight as compared to either component used alone in the polyurethanecomposite material. According to certain embodiments, the effect isnon-additive.

For example, in aromatic thermosetting polyurethanes, using 0.5 wt %Tinuvin 328 light absorber alone provides some resistance to UV, such asreduced yellowing, less chalking, and less embrittlement. Adding Irganox1010 antioxidant at 0.5 wt % greatly improves the resistance to UV, andeven using 0.2 wt % of each provides better stability than either of thestabilizers at 0.5 wt % alone.

Pigment or dye can be added to the polyol mixture or can be added atother points in the process. The pigment is optional, but can help makethe composite material more commercially acceptable, more distinctive,and help to hide any scratches that might form in the surface of thematerial. Typical examples of pigments include iron oxide, typicallyadded in amounts ranging from about 2 wt % to about 7 wt %, based on thetotal weight of the reaction mixture.

Surfactants and Catalysts

One or more catalysts are generally added to control the curing time ofthe polymer matrix (upon addition of the isocyanate), and these may beselected from among those known to initiate reaction between isocyanatesand polyols, such as amine-containing catalysts, such as DABCO andtetramethylbutanediamine, tin-, mercury- and bismuth-containingcatalysts. To increase uniformity and rapidity of cure, it may bedesirable to add multiple catalysts, including a catalyst that providesoverall curing via gelation, and another that provides rapid surfacecuring to form a skin and eliminate tackiness. For example, a liquidmixture of 1 part tin-containing catalyst to 10 parts amine-containingcatalyst can be added in an amount greater than 0 wt % and below about0.10 wt % (based on the total reaction mixture) or less, depending onthe length of curing time desired. Too much catalyst can result inovercuring, which could cause buildup of cured material on theprocessing equipment, or too stiff a material which cannot be properlyshaped, or scorching; in severe cases, this can lead to unsaleableproduct or fire. Curing times generally range from about 5 seconds toabout 2 hours.

A surfactant may optionally be added to the polyol mixture to functionas a wetting agent and assist in mixing of the inorganic particulatematerial. The surfactant also stabilizes and controls the size ofbubbles formed during foaming (if a foamed product is desired) andpassivates the surface of the inorganic particulates, so that thepolymeric matrix covers and bonds to a higher surface area. Surfactantscan be used in amounts below about 0.5 wt %, desirably about 0.3 wt %,based on the total weight of the mixture. Excess amount of surfactantcan lead to excess water absorption, which can lead to freeze/thawdamage to the composite material. Silicone surfactants have been foundto be suitable for use in the invention. Examples include DC-197 andDC-193 (silicone-based, Air Products), and other nonpolar and polar(anionic and cationic) products.

Other Additives

In some embodiments, the filled polyurethane composite materialadditionally comprises at least one coupling agent. Coupling agents andother surface treatments such as viscosity reducers or flow controlagents can be added directly to the filler or fiber, and incorporatedprior to, during, and after the mixing and reaction of the polyurethanecomposite material. In some embodiments, the polyurethane compositematerials comprise pre-treated fillers and fibers.

In some embodiments, the coupling agents allow higher filler loadings ofan inorganic filler such as fly ash. In embodiments, these ingredientsmay be used in small quantities. For example, the polyurethane compositematerial may comprises about 0.01 wt % to about 0.5 wt % of at least onecoupling agent. In some of these embodiments, the polyurethane compositematerials exhibit greater impact strength, as well as greater flexuralmodulus and strength, as compared to those materials without at leastone coupling agent. Coupling agents reduce the viscosity of theresin/filler mixture. In some embodiments, coupling agents increase thewetting of the fibers and fillers by the resin components during themixing the components.

In other embodiments, coupling agents reduce the need for colorants byimproving the dispersion of the colorants, and the break up of colorantclumps. Thus, the polyurethane composite material which comprisescoupling agents and a colorant may exhibit substantially uniformcoloration throughout the polyurethane composite material.

Example in Table 5: The following flow control agents were tested in aurethane polyol with a high loading of filler, such that the combinationwould flow through a Zahn #5 cup viscometer. The polyol was BayerMultranol 4035 polyether used at 70 g, with 30 g of two differentfillers—tested separately. The polyol+filler were hand mixed and putinto the Zahn Cup with the bottom port closed with tape. When the Zahncup was full, the tape was removed and the time for the mixture to flowout of the Cup was measured. All tests at 65° F. (18° C.). The agentswere: Air Products DABCO DC197 silicone-based surfactant, KenrichPetrochemicals Ken-React LICA 38, and Ken-React KR 55 organo-titanates,Shin-Etsu Chemical KBM-403 organo-silane.

These tests show that even 0.1% of the flow control agent on the weightof the filler can markedly improve the flow of the mixture. This flowimprovement allows higher levels of filler to be used in urethanemixtures, better wetting of the filler by the polyol, and more thoroughmixing of all the components. The DC-197 surfactant works well, but onlyat much higher concentrations.

TABLE 5 Time to Flow out of #5 Zahn % Flow Cup, & Improvement Improverstop (Faster Weight, dripping, Flow) Filler Type Flow Improver gramsseconds Over Control Ground None (Control) — 60 — waste bottle glassGround KBM 403 0.14 50 15% waste bottle glass Ground KBM 403 0.51 g +1.34 53 18% waste bottle DC-197 0.83 g glass Ground KBM 403 0.15 g +0.75 56  7% waste bottle DC-197 0.60 g glass Ground DC-197 0.67 50 13%waste bottle glass Cinergy fly None (Control) — 46 — ash Cinergy fly KBM403 0.21 38 17% ash Cinergy fly KR 55 0.06 41 11% ash Cinergy fly LICA38 0.04 42 13% ash Cinergy fly KBM 403 0.03 40 16% ash

Ratios of the Components Used to Make the Polyurethane CompositeMaterial

Variations in the ratio of the at least one polyol to the isocyanatehave various changes on the overall polyurethane product and the processfor making the polyurethane composites with high inorganic filler loads.High filler in such systems typically inhibit or physically block thereaction or action of the various polyurethane composite components,including the at least one polyol, the di- or polyisocyanate, thesurfactants, flow modifiers, cell regulators and the catalysts. Inaddition, the heat that is released during the course of the exothermicreaction in forming the polyurethane composite is much higher in anunfilled polyurethane system. A larger isocyanate index gives highertemperature exotherms during the process of making the polyurethanecomposite material. By adding, 5 to 20 wt % excess, and more preferably5 to 10 wt % excess, of the isocyanate to the otherwise chemicallybalanced at least one polyol that may comprise chain extenders withadditional OH groups (thus, measuring the balance by the overall OHnumbers).

Higher temperature exotherms result in more cross linking of the polyoland isocyanate, and/or a more complete reaction of the hydroxyl groupsand isocyanate groups. In some embodiments, a higher isocyanate indexalso causes much higher cross link densities. In other embodiments, thehigher isocyanate index provides a more “thermoset” type of polyurethanecomposite. In other embodiments, the higher isocyanate index provides apolyurethane with a more chemically resistant polyurethane compositematerial when exposed to chemicals. In some cases, these chemicals aresolvents and water. In certain embodiments, the higher isocyanate indexprovides a polyurethane composite system with a higher heat distortiontemperature. The heat distortion temperature or its effects may bedetermined by elevated temperature creep tests, standard ASTM heatdistortion testing, surface hardness variations with increasedtemperature, for example, in an oven, and changes in mechanicalproperties at increasing temperature.

Representative suitable compositional ranges for synthetic lumber, inpercent based on the total composite composition, are provided below:

At least one polyol: about 6 to about 28 wt %

Surfactant: about 0.2 to about 0.5 wt %

Skin forming catalyst about 0.002 to about 0.01 wt %

Gelation catalyst about 0.02 to about 0.1 wt %

Water 0 to about 0.5 wt %

Chopped fiberglass 0 to about 10 wt %

Pigments 0 to about 6 wt %

Inorganic particulates about 60 to about 85 wt %

Isocyanate about 6 to about 20 wt %

Axial tows 0 to about 6 wt %.

Additional components described herein can be added in various amounts.Such amount may be determined by persons having ordinary skill in theart.

Mixing and Reaction of the Components of the Polyurethane CompositeMaterial

The polyurethane composite material can be prepared by mixing thevarious components described above including the isocyanate, the polyol,the catalyst, the inorganic filler, and various other additives. In someembodiments, one or more other additives may be mixed together with thecomponents of the polyurethane composition. One or more component resinscan be heated to melt prior to the mixing or the composition may beheated during the mixing. However, the mixing can occur when eachcomponents is in a solid, liquid, or dissolved state, or mixturesthereof. In one embodiment, the above components are mixed together allat once. Alternatively, one or more components are added individually.Formulating and mixing the components may be made by any method known tothose persons having ordinary skill in the art, or those methods thatmay be later discovered. The mixing may occur in a pre-mixing state in adevice such as a ribbon blender, followed by further mixing in aHenschel mixer, Banbury mixer, a single screw extruder, a twin screwextruder, a multi screw extruder, or a cokneader.

In some preferred embodiments, the polyurethane composite material canbe prepared by mixing the polyols together (if multiple polyols areused), and then mixing them with various additives, such as catalysts,surfactants, and foaming agent, and then adding the inorganicparticulate phase, then any reinforcing fiber, and finally theisocyanate. While mixing of some of the components can occur prior toextrusion, all of the components may alternatively be mixed in a mixersuch as an extruder.

In one embodiment, it has been found that this order of blending resultsin the manufacture of polyurethane composite materials suitable forbuilding material applications. Thus, it has been discovered that theorder of mixing, as well as other reaction conditions may impact theappearance and properties of the resulting polyurethane compositematerial, and thus its commercial acceptability.

One particular embodiment relates to a method of producing a polymermatrix composite, by (1) mixing a first polyol and a second polyol witha catalyst, optional water, and optional surfactant; (2) optionallyintroducing reinforcing fibrous materials into the mixture; (3)introducing inorganic filler into the mixture; (4) introducing poly- ordi-isocyanate into the mixture; and (5) allowing the exothermic reactionto proceed without forced cooling except to control runaway exotherms.

The process for producing the composite material may be operated in abatch, semibatch, or continuous manner. Mixing may be conducted usingconventional mixers, such as Banbury type mixers, stirred tanks, and thelike, or may be conducted in an extruder, such as a twin screw,co-rotating extruder. When an extruder is used, additional heating isgenerally not necessary, especially if liquid polyols are used. Inaddition, forced cooling is not generally required, except for minimalcooling to control excessive or runaway exotherms.

For example, a multi-zone extruder can be used, with polyols andadditives introduced into the first zone, inorganic particulatesintroduced in the second zone, and chopped fibers, isocyanate, andpigments introduced in the fifth zone. A twin screw, co-rotating,extruder (e.g. 100 mm diameter, although the diameter can be variedsubstantially) can be used, with only water cooling (to maintainsubstantially near room temperature), and without extruder vacuum(except for ash dust). Liquid materials can be pumped into the extruder,while solids can be added by suitable hopper/screw feeder arrangements.Internal pressure build up in such an exemplary arrangement is notsignificant.

Although gelation occurs essentially immediately, complete curing cantake as long as 48 hours, and it is therefore desirable to wait at leastthat long before assessing the mechanical properties of the composite,in order to allow both the composition and the properties to stabilize.

Extrusion

As discussed above, particular methods related to extruding polyurethanecomposite materials. One particular method includes extruding thepolyurethane composite materials as described herein through an extruderhaving various segments and multiple screw elements

Referring to FIG. 4, one example of an extruder suitable for formingpolyurethane composite materials may include up to nine barrel segments.As shown, each barrel segment includes at least one screw element. Inaddition, some or all of the barrel segments have a material input port.

In a first segment of the extruder, the at least one polyol may beintroduced to the extruder. In some embodiments, the at least one polyolmay include a blend of one or more polyols. Additionally, the at leastone polyol may be blended with one or more of the catalyst, surfactants,blowing agents and other components described herein. In someembodiment, each components may be added individually or together. Insome embodiments, the components are preblended prior to introduction tothe extruder. As shown in FIG. 4, a first segment of the extruderincludes a transport screw. As the transport screw is driven, the atleast one polyol and optional other components are transported by thescrew toward the output end of the extruder

In a second segment of the extruder, inorganic filler material such asash may be introduced to the extruder. The inorganic filler material isblended with the components from the first segment. As shown in FIG. 4,a second segment of the extruder includes a transport screw. Thetransport screw may further transfer the components from the first andsecond segments of the extruder toward the output end of the extruder.As the first and second segment include a transport screw, the first andsecond segment may be classified as a first conveying section.

Components inputted in a first or second segment may be transferred to athird segment of the extruder by the screw. In a third segment of theextruder, previously inputted components may be mixed further by slottedscrews. A third segment may also include lobal screws. In someembodiments, the mixing provides a substantially uniform mixture of oneor more of least one polyol, at least one catalyst, a surfactant, anoptional blowing agent, pigment, and filler. These components experiencemore shearing forces created by the slotted screw. The previousintroduced components may then be further transferred toward the outputend of the extruder. In some embodiments, the components are transferredto a fourth segment of the extruder. As shown in FIG. 4, a fourthsegment may contain one or more of lobal and slow transport screws. Asthe third and fourth segments may contain mixing elements, such segmentsmay be classified as a first mixing section. This screw providesadditional mixing to provide a more homogenous mixture of thecomponents. This screw also may provide good wetting of the fillers andfibers. It has been discovered that lobal screws provide a morehomogeneous mixture of the previously introduced components.

In some embodiments, the isocyanate components may be introducedsubsequent to the polyol component. As shown in FIG. 4, the isocyanatecomponent (monomeric or oligomeric di- or polyioscyanate) is introducedin a subsequent segment of extruder related to the segment in which theat least one polyol was introduced. More specifically, the isocyanatecomponent is introduced in a fifth segment of the extruder. In someembodiments, a reaction may begin to occur between the at least onepolyol and the at least one isocyanate. However, a delayed actioncatalyst may used to substantially prevent overreaction of thecomponents until the composite material has exited the extruder. As thereaction between the at least one polyol and the at least one isocyanateis exothermic, cooling may be required. Cooling may also be required insubsequent barrel segments. In previous barrel segments, cooling isgenerally not required as no reaction has occurred. However, cooling maybe provided to previous barrel segments according to some embodiments.

As shown in FIG. 4, the fifth segment may contain a screw element suchas a transport screw element. The transport screw may provide mixing ofthe isocyanate and previously added components including at least onepolyol and the inorganic filler. To allow substantially thorough mixingof these components, one or more mixing screw elements may be used. Thetransport screw of the fifth segment may transfer the at least onepolyol, the inorganic filler, and the isocyanate (and optional otheradditives) to a subsequent segment. Such subsequent segment may be allor a portion of a second mixing section. In some embodiments, thesecomponents are transferred to a sixth segment as shown in FIG. 4.

In a sixth barrel segment or in the second mixing section, a reversescrew provides a substantial amount of mixing to the previous addedcomponents of the composite mixture. In some embodiments, substantialshearing is provided to the composite mixture. As a reverse screw hasnegative pitch, the components of the composite material may be blockfrom being transferred through such a segment until sufficient shearingforces and pressure allow the mixture to pass through this segment. Insome embodiments, the reverse screw is configured to block the mixtureback to a subsequent segment or section. For example, the entire mixturemay be blocked to one or more of the first segment, second segment,third segment, fourth segment, or fifth segment. In another embodiment,the components of the mixture are blocked to one or more of the firstconveying section, second conveying section, or the first mixingsection. Such shearing together with the exothermic reaction of thepolyol and the isocyanate may require cooling in the segment or section.

Vents may be disposed on either side of the second mixing section. Aslarge amounts of mixing may release entrained air in the one or morecomponents of the polyurethane composite mixture, such air must bereleased. Additionally, gas produced by the blowing agent may berequired to be released. In some embodiments, a vacuum may be used toremove the entrained air and/or gas from the blowing agent. In someembodiments, the removed air or gas results in the formation of a moredense and uniform polyurethane composite material.

In optional embodiments, fiber rovings may be added to the compositemixture in a subsequent segment. This segment may be found in a thirdconveying section. As shown in FIG. 4, fibrous material may beintroduced in a seventh segment of the extruder. Such a segment may alsocontain a transport screw. In particular embodiments, the transportscrew may be a fast transport screw. In some embodiments, the fasttransport screw has fewer screw threads per unit of length as comparedto a slow transport screw. The transport screw of the segment mayintroduce, chop up, and mix the fiber rovings.

In subsequent segments, the mixture may be further mixed and transportedtoward the output end of the extruder. Such subsequent segments mayconstitute a second or third mixing section, depending on theembodiment. For example, in an eighth segment, lobal screws may providefurther mixing to the composite mixture. In addition, a reverse screwmay be provided in this or subsequent segments to provide substantialmixing and/or shearing of the components of the composite mixture.

As mentioned above a mixing section adjacent to the output end of theextruder may include one or more reverse screws and lobal screws. Insome embodiments, a reverse screw is in the last segment of theextruder. In some embodiments, the reverse screw is a reverse slottedscrew. As enough shearing forces and/or pressure transfer the mixturepast the reverse screw, the mixture is extruded through a die.

In some embodiments, the extruder has a L/D of about 10 to about 40. Insome embodiments, the extruder has a L/D of about 10 to about 15. Insome embodiments, the extruder has a L/D of about 20 to about 40. Insome embodiments, the extruder has a L/D that is greater than about 24.In some embodiments, the extruder may operate from between about 200 toabout 2000 rpm.

FIG. 5 represents one configuration of an extruder for the introductionof the components materials as described above. This extruder includes afirst conveying section C₁, a first mixing section M₁, a secondconveying section C₂, and a second mixing section M₂. A feed end isshown on the right and an output end on the left.

In accordance with some embodiments, foaming of the polyurethanecomposite materials occurs after the die. In some embodiments, somefoaming and reaction of the composite mixture may occur prior to orduring extrusion.

Other alternatives may be used when providing the mixed polyurethanecomposite material. For example the extruder may have more than or lessthan nine barrel segments. In some embodiments, certain types of screwscan be replaced by a different type of screw. These variations should beapparent to a person having ordinary skill in the art.

Forming

In some embodiments, the process of forming the highly filledpolyurethane composite material comprises providing the components ofthe polyurethane composite material, mixing the components together,extruding the components through a die, adding any other additionalcomponents after the extrusion, and forming a shaped article of thepolyurethane composite material. As the polyurethane composite materialexits the die, the composite material may be placed in a mold forpost-extrusion curing and shaping. In one embodiment, the compositematerial is allowed to cure in a box or bucket.

In one embodiment the formation of the shaped articles comprisesinjecting the extruded polyurethane composite material in a mold cavityand curing the shaped article. However, some embodiments require thatthe extruded polyurethane composite material be placed in a mold cavitysecured on all sides, and exerting pressure on the polyurethanecomposite material. In some of these embodiments, the polyurethanecomposite material will be foaming or will already be foamed. However,it is preferred that the material is placed under the pressure of themold cavity prior to or at least during at least some foaming of thepolyurethane composite material.

A shaped article can be made using the polyurethane composite materialsaccording to the foregoing embodiments. In some embodiments, thisarticle is molded into various shapes. In some embodiments, thepolyurethane composite material is extruded, and then injected into acontinuous production system. Suitable systems for forming the compositematerials of some embodiments are described in U.S. patent applicationSer. No. 10/764,013 filed Jan. 23, 2004 and entitled “CONTINUOUS FORMINGSYSTEM UTILIZING UP TO SIX ENDLESS BELTS,” now published as U.S. PatentApplication Publication No. 2005-0161855-A1, and U.S. patent applicationSer. No. 11/165,071, filed Jun. 23, 2005, entitled “CONTINUOUS FORMINGAPPARATUS FOR THREE-DIMENSIONAL FOAMED PRODUCTS,” now published as U.S.Patent Application Publication No. 2005-0287238-A1, both of which arehereby incorporated by reference in their entireties.

The polyurethane composite material of certain embodiments may exertcertain pressures on the walls of any mold, such as that found in theforming devices as described above. While the amount of pressure mayvary according to the amount of foaming and gas production, it ispreferred that such forming devices may exert or hold pressures by themold cavity ranging from about 35 to about 75 psi. In some embodiments,the pressure is from about 45 to about 65 psi. In some embodiments, thepressure is about 50 psi. However, mold pressures in any embodiment of amethod of making the polyurethane composite material can be higher thanor less than the specified values. The exact pressure required in theformation of the desired shaped article depends on the density, color,size, shape, physical properties, and the mechanical properties of thearticle comprising the polyurethane composite material.

When foaming polyurethane is formed by belts into a product shape, thepressure that the belts exert on the foamed part is related to theresulting mechanical properties. For example, as the pressure of thefoaming increases and the belt system can hold this pressure without thebelts separating, then the product may have higher flexural strength,then if the belts allowed leaking, or pressure drop. In someembodiments, pressures about 50 to about 75 psi have been used to obtainhigh mechanical properties in the polyurethane composite material. Inone example, an increase in the flexural strength of 50 psi results fromthe higher pressure in the belts, versus using a lower pressure.

In some embodiments, a shaped article comprising the polyurethanecomposite material as described herein is roofing material such as rooftile shingles, etc., siding material, carpet backing, synthetic lumber,building panels, scaffolding, cast molded products, decking materials,fencing materials, marine lumber, doors, door parts, moldings, sills,stone, masonry, brick products, post, signs, guard rails, retainingwalls, park benches, tables, slats and railroad ties.

Other shaped articles may comprise a portion of which comprises thepolyurethane composite material. In some embodiments, the polyurethanecomposite material is coated or molded on one side of an article. Forexample, the polyurethane composite material may be coated or moldedonto one side of a flat or S-shaped clay roof tile, which has been cutthinner than normal, and laid on a conveyor belt, followed by extrusionof the polyurethane composite material onto at least a portion of thetile. Such portion may be shaped by a mold which is adapted to shape thepolyurethane composite material deposited on the tile. For example, theforming unit may operate with two mold belts which are adapted to shapethe polyurethane composite material on one side of the portion. In someembodiments, the composite material may provide backing to an article.In one embodiment, the composite material may be foamed sufficient toprovide insulation to an article.

In some embodiments, the polyurethane composite material can reinforcean article. For example, by placing a coating or molding of thepolyurethane composite material on a roof tile, the impact strength ofthe roof tile is increased. Thus one embodiment comprises a method ofsubstantially reducing the fracture of an article by depositing thepolyurethane composite on a solid surface article, shaping the compositeon the solid surface article by methods described herein, and curing thecomposite on the solid surface article. Such method may produce a one ormore of a reinforced, backed, or insulated article. Such article mayalso have increased physical and mechanical properties. Additionally, areinforcing layer may be used to prevent water weeping, and increasesthe overall thickness of a solid surface article.

In some embodiments, the polyurethane composite material can bonddirectly to an article solid surface article such as a tile.Alternatively, an adhesive can be applied to the solid surface articleand a shaped polyurethane composite article can be attached thereto. Asolid surface article such as a tile may include at least one or more ofcement, slate, granite, marble, and combinations thereof; and thepolyurethane composite material as described in embodiments herein. Suchtiles may be used as roofing or siding tiles.

In some embodiments, the composite material may be used as reinforcementof composite structural members including building materials such asdoors, windows, furniture and cabinets and for well and concrete repair.In some embodiments, the composite material may be used to fill anyunintended gaps, particularly to increase the strength of solid surfacearticles and/or structural components. Structural components may formedfrom a variety of materials such as wood, plastic, concrete and others,whereas the defect to be repaired or reinforced can appear as cuts,gaps, deep holes, cracks.

Optional Additional Mixing Process

One of the most difficult problems in forming polyurethane compositematerials which have large amounts of filler is getting intimatemixing—blending the polyols and the isocyanate. In some embodiments, anultrasound device may be used to cause better mixing of the variouscomponents of the polyurethane composite material. In these embodiments,the ultrasound mixing may also result in the enhanced mixing and/orwetting of the components. In some embodiments, the enhanced mixingand/or wetting allows a high concentration of filler, such as coal ashto be mixed with the polyurethane matrix, including about 40, 50, 60,70, 80, and about 85 wt % of the inorganic filler.

In some embodiments, the ultrasound device produces an ultrasound of acertain frequency. In some embodiments, the frequency of the ultrasounddevice is varied during the mixing and/or extrusion process. In someembodiments, the components are mixed in a continuous mixer, such as anextruder, equipped with an ultrasound device. In some embodiments, anultrasound device is attached to or is adjacent to the extruder and/ormixer. In other embodiments, an ultrasound device is attached to the dieof the extruder. In other embodiments, the ultrasound device is placedin a port of the mixer. In further embodiments, an ultrasound deviceprovides vibrations at the location where the isocyanate and polyol meetas the screw delivers the polyol to the isocyanate.

In addition, an ultrasound device may provide better mixing for theother components, such as blowing agents, surfactants, catalysts. Inembodiments where additional components are added to the polyol prior tomixing the polyol with the isocyanate, the additional components arealso exposed to ultrasound vibration. In some embodiments, an ashselected from fly ash, bottom ash, or combinations thereof, is mixedusing an ultrasound device. In some embodiments, ultrasound vibrationsbreaks up filler and fiber bundles to allow more thorough wetting ofthese components to provide a polyurethane composite material withbetter mechanical properties, such as flexural modulus and flexuralstrength, as compared to polyurethane composite materials which arecreated without the use of ultrasound vibration. The wetting of fibersand fillers could also be increased by the use of ultrasound at or nearthe die of the extruder, thus forcing resin to coat the fibers andfillers better, and even breaking up fiber bundles and filler lumps. Thesound frequency and intensity would be adjusted to give the best mixing,and what frequency is best for the urethane raw materials, may not bebest for the filler and fibers.

Unless otherwise noted, all percentages and parts are by weight.

The skilled artisan will recognize the interchangeability of variousfeatures from different embodiments. Similarly, the various features andsteps discussed above, as well as other known equivalents for each suchfeature or step, can be mixed and matched by one of ordinary skill inthis art to perform compositions or methods in accordance withprinciples described herein. Although the invention has been disclosedin the context of certain embodiments and examples, it will beunderstood by those skilled in the art that the invention extends beyondthe specifically disclosed embodiments to other alternative embodimentsand/or uses and obvious modifications and equivalents thereof.Accordingly, the invention is not intended to be limited by the specificdisclosures of embodiments herein. Rather, the scope of the presentinvention is to be interpreted with reference to the claims that follow.

1. A method of forming a polymeric composite material in an extruder,the method comprising: introducing at least one polyol and inorganicfiller to a first conveying section of the extruder; transferring the atleast one polyol and inorganic filler to a first mixing section of anextruder; mixing the at least one polyol and the inorganic filler in thefirst mixing section; transferring the mixed at least one polyol andinorganic filler to a second conveying section of the extruder;introducing a di- or poly-isocyanate to the second conveying section;transferring the mixed at least one polyol and inorganic filler and thedi- or poly-isocyanate to a second mixing section; mixing the mixed atleast one polyol and inorganic filler with the di- or poly-isocyanate inthe second mixing section of the extruder to provide a compositemixture; and transferring the composite mixture to an output end of theextruder.
 2. The method of claim 1, wherein the extruder is a twin screwextruder.
 3. The method of claim 1, wherein the composite mixturecomprises about 40 to about 85 weight percent of the inorganic filler.4. The method of claim 1, wherein the composite mixture comprises about60 to about 85 weight percent of the inorganic filler.
 5. The method ofclaim 1, wherein the composite mixture comprises about 65 to about 80weight percent of the inorganic filler.
 6. The method of claim 1,wherein the inorganic filler is fly ash.
 7. The method of claim 1,wherein the first conveying section comprises one or more transferscrews.
 8. The method of claim 1, wherein the first mixing sectioncomprises a slotted screw.
 9. The method of claim 1, wherein the firstmixing section comprises a lobal screw.
 10. The method of claim 1,wherein the first mixing section comprises a lobal screw and a slottedscrew.
 11. The method of claim 1, wherein the second conveying sectioncomprises a transfer screw.
 12. The method of claim 1, wherein thesecond mixing section comprises a reverse screw.
 13. The method of claim12, wherein the reverse screw comprises a reverse slotted screw.
 14. Themethod of claim 1, further comprising adding one or more components ofthe composite mixture in the first conveying section of the extruder,the one or more components being selected from the group consisting of acatalyst, a surfactant, and a blowing agent.
 15. The method of claim 14,further comprising blending the one or more components with the at leastone polyol prior to introduction to the first conveying section.
 16. Themethod of claim 1, further comprising mixing the mixed at least onepolyol and inorganic filler and the di- or poly-isocyanate in a thirdmixing section subsequent to the second conveying section and prior tothe second mixing section.
 17. The method of claim 16, wherein the thirdmixing section comprises a reverse screw.
 18. The method of claim 16,further comprising introducing fibrous material in a third conveyingsection, the third conveying section being located between the secondmixing section and the third mixing section.
 19. The method of claim 1,further comprising introducing fibrous material in the second conveyingsection.
 20. The method of claim 19, further comprising mixing thefibrous material with the mixed at least one polyol and inorganic fillerand the di- or poly-isocyanate in the second mixing section.